The present invention relates to rotary cutter, particularly for shredding tobacco, of the type comprising:
a fixed support structure,
a shaft supported by the structure for rotation about an axis,
at least one blade-holder carriage which can rotate with the shaft and carries at least one cutting blade for cutting through and penetrating a block of tobacco supplied in a direction such that it is inclined at an angle to the axis, the carriage being able to perform a translatory movement relative to the shaft along a line parallel to the axis,
motor means for rotating the shaft, and
drive means for bringing about the translatory movement of the carriage and of the associated blade in synchronism with the rotation of the shaft.
A rotary cutter of this type is described in European patent application 0 293 384.
In this known device, the drive means comprise a stationary cam with a shaped guide profile and the blade-holder carriages have respective cam followers which cooperate with the cam profile, and thrust means for urging the cam follower against the guide profile of the cam.
With this solution the magnitude and speed of the translatory movement or traverse of the blade-holder carriages which can be achieved during the fraction of each revolution in which the associated blade is cutting through the block of tobacco are quite limited.
Moreover, in the device according to the document mentioned above, all the blade-holder carriages are subjected to a translatory movement to and fro for each revolution of the shaft, with considerable stress and wear of their guides.